A practical
necessity in any method of counterfeit identification is the
availability of known genuine components of the same type. Except in
instances of truly outlandish components (misspellings on the label, no
die in the package, etc.), having genuine parts for comparative analysis
makes counterfeit identification much easier, especially in components
where some features fall in a gray area. (Are those delaminations
extensive enough to prove counterfeiting, or are they just unusually
sloppy work by the OEM?)

Component users encounter two different
types of counterfeit parts. By far the most common is the “recycled”
ICs that began life, generally five to 15 years ago, as a new, genuine
component from a legitimate component manufacturer. Eventually the
circuit board it resided on was scrapped and shipped offshore, where the
entire component population was burned off for refurbishment,
remarking, repackaging and reintroduction as new into the global supply
chain. SMT Corp. estimates recycled ICs comprise 80 to 90% of all
counterfeits currently in circulation worldwide.

A small
percentage of counterfeit components are “made-from-scratch” – or
knock-offs. A foreign counterfeiter with component manufacturing
capability finds it worthwhile to replicate the entire component
altogether – and does so without the permission of the original IP
holder. The chip and other internal features may be nonfunctional or
even absent, or – worse yet – functional!

The vast majority of
recycled counterfeits undergo a process something like this: The board
is heated in an uncontrolled harsh environment (usually an open-flame
fire) until solder reflows, at which time the board is smacked against a
hard surface to remove the components. The components from hundreds or
even thousands of similar boards are collected and washed (sometimes in a
nearby river, sometimes outside in the rain) to remove residue from the
high-heat removal process, and then sun-dried. Most are then
rough-sorted by sifting and then hand-sorted by part number or similar
package style. In many cases, components of different manufacturers,
vastly different functions and electrical characteristics wind up in the
same finished counterfeit lot, as long as they have the same number of
leads and the same package dimensions.

The original component
part markings are then removed (generally by rubbing the component by
hand against sandpaper tacked to a table). A “blacktop” coating that
more or less approximates the texture and color of the original mold
compound surface is painted or sprayed onto the component’s top surface
to cover the sanding marks. Last, the top surface is reprinted
(remarked) with a legitimate-looking manufacturer’s logo, part number
and more recent lot/date code. They are then packaged in what looks like
(and may actually be) authentic original component manufacturer (OCM)
packaging and offered for sale as new product direct from the
manufacturer.

The longevity of functioning counterfeits is, of
course, questionable indeed. It should be pointed out, given the huge
volume of containers recycled each year, that it is perfectly possible
for the same component to be recycled multiple times. For the successful
counterfeiter, external appearance of authenticity at the point of sale
is what matters most; downstream functional issues become someone
else’s problem.

The efforts of counterfeiters to mimic the
appearance of genuine components involve considerable innovation. While
some methods are still crude, many are not. In July 2009, SMT Corp.
was the first to identify a new, harder to detect blacktopping material
that, when applied carefully, looked almost identical to the OCM’s top
coating. Traditionally the paint-like blacktopping material has easily
been identified by a solvent swab of pure acetone, or even a much milder
75/25% mixture of mineral spirits and alcohol. These solvents would
dissolve the traditional blacktop coatings and reveal visual evidence
left behind by the counterfeit process of removing original part
markings.

This new advanced blacktop material is harder to
distinguish visually from the surface of a genuine part, and is not
affected whatsoever by traditional RTS test methods. An engineer
applying traditional solvent testing would conclude it to be a genuine
part. SMT believes this advanced blacktop material is made from the dust
ground off components and then mixed with a heat-activated epoxy
compound before being sprayed on and heat-cured for hardness and
durability. In September 2009, Honeywell Aerospace shared its process
using a heated solvent called “Uresolve” (made by Dynaloy) that proved
effective in removing the new blacktop coating from counterfeit
components. The only major drawback to the process was it also could
remove the topcoat that OCMs put on the majority of authentic
components. (Factory-applied topcoats, like the blacktopping that
counterfeiters use, can be scraped off with a razor, but they hide no sanding marks.)

In
January, SMT Corp. further refined that process using a different
Dynaloy product called DynaSolve 750. After considerable
experimentation on a wide range of counterfeit and authentic parts, a
temperature/duration process was identified that completely removed the
new blacktop (exposing the sanding marks below) – yet had no effect on
the factory-applied topcoats of all authentic components tested. The
refined process required the DynaSolve be preheated to 105°C and the
suspect component to be half-immersed for 45 min. (Figure 1).

These
same components showed other signs of counterfeiting as well. For
example, the highly engineered blacktop material had been sprayed onto
the top surface, and some had visibly coated the upper portion of the
side of the component. In addition, the blacktop material had in some
cases been sprayed into the pin-one cavities, with the result that the
cavities in close optical view appeared roughly textured rather than
perfectly flat and smooth. Figure 2 is a SEM image of a
portion of one pin-one cavity that has been partly sprayed. Some
cavities, however, were completely clean and resembled those found in
genuine parts.

EDX
analysis compared the results of the new blacktop material with
analysis of the top surface of known genuine components. The results (Figure 3),
while not identical, suggest it is possible that the sprayed-on
blacktop had its origins in the dust created by sanding genuine
components.Another clue was found in the leads of the components. At left in Figure 4
is a light microscope view of two leads from a genuine component.
Because these leads were straight when coated, the forming process
produced some cracking or scaling of the coating at the bend. This is an
expected feature on genuine components. But counterfeiters apply
coatings to leads that are already bent, so cracking and scaling are
absent. The coating applied by counterfeiters also rounds off the lead
ends and conceals the copper base metal visible in the cut-off lead ends
on the genuine parts.

Most
acoustic methods developed by Sonoscan use VHF or UHF ultrasound
reflected from material interfaces at a depth of interest such as the
die surface, the lead frame of die paddle surface, or the die attach
depth. For example, when imaged acoustically, both genuine and
counterfeit components treated with DynaSolve at 105°C show some
internal delaminations at the lead finger depth not present beforehand,
an indication that the test should be considered destructive.

The
same C-SAM acoustic micro imaging system that images internal features
can also image surfaces acoustically. It can also characterize a
material at the same time it is making an acoustic image.

One of
the oldest methods for spotting possibly counterfeit components is the
simple application of a single pulse of ultrasound to determine the mold
compound’s acoustic impedance (acoustic velocity times density, the
product expressed in megarayls). If known genuine parts have an acoustic
impedance of around 4.3 megarayls, and an incoming part has an acoustic
impedance of 7.6 megarayls, the new part may be a counterfeit, or the
legitimate supplier may be using a new mold compound. One recent
development: Some made-from-scratch counterfeiters are selecting mold
compounds that attempt to match the acoustic impedance of the genuine
component.

During acoustic imaging of components, it is customary
to scan the top surface of the part by itself for reference. The
surface image gives no information about features at depth, but it turns
out to have value in identifying counterfeits when the bottom surface,
which is ordinarily not of interest, is also imaged. In genuine
components, both surfaces appear identical acoustically because they
were formed from the same material during the same injection molding
process. But in a recycled fake where the top has been blacktopped, the
two sides often look very different. (Figure 5).

When an acoustic micro imaging system targets a specific depth within a counterfeit, strange things are sometimes found. Figure 6
shows two outwardly identical components having the body dimensions,
the same label and the same number of leads. But the acoustic image
shows that the component at bottom is either a newer die revision from
the manufacturer utilizing a smaller die or is from a different
component manufacturer altogether and uses entirely different die and
lead frame. It also has small delaminations (red and yellow) on nearly
all of the lead fingers.

One
of the areas of interest in any acoustic image of a component is the
percentage of delaminations or similar defects in the die attach
material. For example, J-STD-020D, sec. 6.2.1.1, specifies that metal
lead frame components may have “no delamination/cracking >50% of the
die attach area in thermally enhanced packages or devices that require
electrical contact to the backside of the die.” New, genuine components
may have some percentage of delamination and be perfectly acceptable for
most applications. Recycled components may show a relatively greater
degree of delamination, presumably because of the thermal and mechanical
stresses of prior use and of the counterfeiting process itself. Figure 7
shows the acoustic image of a known counterfeit component whose die
attach delaminations (red areas) exceed the standard. Digital image
analysis showed delaminations covered 57.12% of the die attach area.

It
may be difficult to tell whether a particular component with above
average die attach voiding is simply an isolated item from a good OEM,
or whether this component has been heated irregularly, smacked on the
ground and washed in a river. Determining whether a part is counterfeit
is easier if multiple questionable parts and multiple known genuine
parts are available in order to look for patterns. One group of
counterfeits seen in Sonoscan’s laboratory had varying delaminations,
some covering only part of the die paddle, and some extending onto the
die face. The corresponding group of known genuine parts all had smaller
delaminations, all on the same corner of the die paddle.

Collaboration
between SMT and Sonoscan has resulted in the identification of internal
features not previously seen acoustically in components. Figure 8
is the acoustic image of a pair of components. The genuine part at top
shows minimal defects. The recycled counterfeit at bottom shows numerous
delaminations (red, yellow) on the die paddle and on the tape. But it
also shows a surprising feature: two over-bright regions (arrows) near
the bottom edge. Something has happened along this edge to make the
interface between the mold compound and the lead fingers appear brighter
than elsewhere, and the upper edge of this phenomenon is marked by a
dark line. Two possible explanations: Sanding may have altered the top
edge of the component, causing the returning ultrasonic echoes to bend;
or heat may have re-cured or otherwise altered the mold compound in this
region, but without creating a gap (delamination), which would be red
or yellow. Strange effects seem to occur when components are subjected
to heat, mechanical shock and moisture in uncontrolled environments.

This
brief article has not covered all of the techniques currently available
to identify counterfeit components, but it demonstrates what may be
accomplished with the innovative use of technological resources. Since
counterfeiters are actively responding to detection methods, new
detection methods will continually be developed to keep counterfeit
parts out of production.

Dr. Lawrence W. Kessler is president of Sonoscan (sonoscan.com). Thomas Sharpe is vice president of SMT Corp. (smtcorp.com);
tsharpe@smtcorp.comThis e-mail address is being protected from spambots. You need JavaScript enabled to view it
.